11.3.3 Main Clock After Reset
After any Reset, CLK_MAIN is provided by the 16 MHz Oscillator (OSC20M) and with a prescaler
division factor of 6. Since the actual frequency of the OSC20M is determined by the Frequency
Select bits (FREQSEL) of the Oscillator Configuration fuse (FUSE.OSCCFG), these frequencies
are possible after Reset:
CLK_MAIN |
Resulting CLK_PER |
---|---|
16 MHz | 2.66 MHz |
See the OSC20M description for further details.